It was analyzed the possible allelopathic action of vegetal remains of black oat ( Avena strigosa Schreb) (BO) and a consortium (CO) of BO with forage turnip ( Raphanus sativus L.) and vetch ( Vicia sativa L.) in relation to the incidence of weed plants on soybean culture; in intervals (IDS) between covering desiccation with Glyphosate 480 (3 L ha -1) and the cultivar BRS 232 sowing; 5*2.5 m parcels with 1 m of border; four treatments of BO and CO and two control treatments, with five randomized replications, in August, 2006, with 0.15 m among rows. At bloom term, the plots were desiccated in an IDS, of one, ten, twenty and thirty days. The soybean was sown in November 2006, with 0.45 m among rows, thirteen sowing lines and 14 seeds by linear m -1. The incidence of weed plants was evaluated with a 0.5*0.5 m metal frame. The plants were counted and classified by narrow leaf (NL) and large leaf (LL). The soybean harvest was manual and its productivity was adjusted to 13% of water content. The experimental design was completely randomized, in split plot. The data were submitted to normality, while averages were compared by Scott and Knott test at 5% of significance. There was a possible suppressor allelopathic effect of BO and CO coverings on weed plants. The interval between desiccation and sowing interfered on weed population.
